Various types of upflow filter constructions and methods are known in the prior art. One such arrangement is shown in U.S. Pat. No. 3,642,134, dated Feb. 15, 1972. Another such arrangement is disclosed in U.S. Pat. No. 3,950,252, dated Apr. 13, 1976 and assigned to the Assignee of this application. U.S. Pat. No. 3,950,252 discloses a somewhat similar structural arrangement of filter as the present invention, except that the filter construction illustrated is not readily adaptable for use to perform different functions, and ordinarlly requires a distributor to stock a plurality of filter constructions in order to perform satisfactorily under different physical situations.